This invention relates to vegetation cutting devices, and more particularly to cutting attachments for use therewith.
Numerous cutting attachments have been provided for rotatably mounting to vegetation cutting and trimming devices. Most of these cutting attachments, however, are not formed with skid plates which limit snagging during use. In addition, many of these cutting attachments are not self-cleaning and, as a result, collect debris during operation. Accumulated debris can limit the efficiency of the trimming device. Other cutting attachments are formed with skid plates and/or are configured so as to be self-cleaning, but have bodies formed from more than one section (See U.S. Pat. No. 4,856,194). Each section of a cutting attachment generally adds to the cost of manufacture and multisectioned attachments require additional parts for assembly. Cutting attachments currently provided are also usually not interchangeable between cutting devices made by various manufacturers.
Numerous cutting lines and strings and other accessories have also been provided for such cutting attachments. In general, these cutting accessories have a number of disadvantages. Many such cutting blades and strings dull from use and become ineffective. Most such blades are easily damaged if they encounter hard objects during use, particularly if rigidly attached to the cutting attachment. These blades are also generally ineffectual for cutting certain vegetation. Cutting strings currently available are also susceptible to fraying, which can reduce the cutting ability of the string. Cutting strings with protruding edges have also been found to cause significant wear to the cutting attachment, often forming sharp edges therein which can undesirably sever the cutting string.
In general, it is an object of the present invention to provide a cutting attachment which overcomes the limitations and disadvantages of the cutting attachments currently provided.
Another object of the invention is to provide a cutting attachment of the above character which has a unitary lightweight body.
Another object of the invention is to provide a cutting attachment of the above character which has a self-cleaning shape.
Another object of the invention is to provide a cutting attachment of the above character in which any cavities therein are formed from generally smooth and outwardly inclined surfaces to inhibit weeds from becoming caught in the same.
Another object of the invention is to provide a cutting attachment of the above character having a skid plate.
Another object of the invention is to provide a cutting attachment of the above character having an upper cavity and an accessory in the form of a cover plate which can be mounted on the body to overlie the upper cavity.
Another object of the invention is to provide a cutting attachment of the above character which can be readily coupled to various types of cutting devices.
Another object of the invention is to provide a cutting attachment of the above character having improved cutting elements.
Another object of the invention is to provide a cutting attachment of the above character in which the cutting elements include a cutting blade having an inner cutting edge which can be exposed for use after the outermost leading cutting edge has worn.
Another object of the invention is to provide a cutting attachment of the above character in which the cutting blades have serrated cutting edges.
Another object of the invention is to provide a cutting attachment of the above character in which the cutting blades are aerodynamic in design.
Another object of the invention is to provide a cutting attachment of the above character in which the cutting blades are yieldably mounted to the cutting attachment for movement upon contact with an object.
Another object of the invention is to provide a cutting attachment of the above character in which the cutting elements include a cutting string having an inner cutting edge which can be exposed after the outermost cutting edge has worn.
Anotherobject of the invention is to provide a cutting attachment of the above character in which the cutting strings do not cause significant wear to the cutting attachment during use thereof.
Another object of the invention is to provide a cutting attachment of the above character in which the cutting strings inhibit fraying thereof.
Another object of the invention is to provide a cutting attachment of the above character in which the cutting strings have cutting edges which are aerodynamically spiraled in longitudinal configuration.
Another object of the invention is to provide a cutting attachment of the above character which is provided with cutting elements in the form of cutting blades and cutting strings.
These and other objects are achieved in accordance with the invention by providing a cutting attachment for use with a vegetation cutting device having a rotatable drive member. The cutting attachment has a body with a generally planar coupling portion and a central axis of rotation.
In one embodiment, the body further includes a conical central wall portion extending outwardly and in a first direction from the coupling portion and with respect to the axis of rotation and a circular outer wall portion adjoining the central wall portion and extending generally radially outwardly from the axis of rotation. The central wall portion has a generally smooth inner surface which forms a conically-shaped first cavity disposed symmetrically about the axis of rotation. This cavity opens outwardly in the first direction so that it is self-cleaning during operation of the cutting device. The outer wall portion has a generally smooth outer surface free of projections and cavities which serves as a skid plate and is formed to inhibit snagging on objects as the cutting attachment rotates. A second self-cleaning cavity which opens outwardly in an opposite second direction is formed by a generally smooth outer surface of the central wall portion and a generally smooth inner surface of the outer wall portion which inclines outwardly and in the second direction with respect to the axis of rotation.
Coupling means is carried by the coupling portion for coupling the body to the cutting device to cause rotation about the axis of rotation. In one embodiment, the coupling means includes an adapter having first and second clamping elements for clamping the central portion of the cutting attachment therebetween. The second clamping element include means for removably securing the adapter to a rotatable drive member of a trimming device.
A plurality of spaced apart radially extending cutting elements are carried by the body for cutting vegetation as the body rotates about the axis of rotation. These cutting elements can be in the form of cutting blades and/or cutting strings. Cutting blades are provided with aerodynamic configurations, serrated edges, inner and outer cutting edges (the inner edge being exposed after the outer edge is worn), and means for securing the blades to the cutting attachment which permit longitudinal movement of the cutting blade with respect to the cutting attachment. Cutting strings are provided with inner and outer cutting portions (the inner cutting portion being exposed after the outer cutting portion is worn), grooves for reducing fraying and spiraled configurations.